Field of the Invention
Exemplary embodiments of the present invention relate to a shape measurement apparatus and a shape measurement method. More particularly, exemplary embodiments of the present invention relate to a shape measurement apparatus and a shape measurement method capable of enhancing accuracy of measurement.
Discussion of the Background
Electronic devices have been developed to have relatively lighter weight and smaller size. Therefore, possibility of defects in these electronic devices increases and apparatus for inspecting the defects is under development and improvement.
Recently, the technique for inspecting a three-dimensional shape becomes effective in various technical fields. In the technique for inspecting a three-dimensional shape, a coordinate measurement machine (CMM), which detects three-dimensional shape by a contacting method, was used. However, non-contact method for inspecting a three-dimensional shape by using optical theories has been under development.
Meadows and Takasaki developed shadow Moire method which is the representative non-contact method for inspecting a three-dimensional shape in 1970. However, the shadow Moire method has a problem that a grating for measurement should be larger than a measurement target in size. In order to solve the above problem, Yoshino developed the projection Moire technique. Additionally, Kujawinska applied the phase shifting method which is used for analysis of optical coherence to Moire technique for inspecting three-dimensional shape so that the measurement resolution is enhanced and the limitation of Moire pattern is removed.
These techniques for measuring three-dimensional shape may be used for inspection of a printed circuit board, and tries for enhancing accuracy are performed.